Which was ventures contribution to science

Sammi is studying the interaction of the digestive and circulatory systems in the human body. she has listed various processes that occur in each of the systems. put the processes in order to describe the interaction between these two systems. tiles nutrients diffuse through the villi of the small intestine.digestive processes break nutrients down in the mouth, stomach, and small intestine.blood is pumped through the circulatory system to deliver nutrients to other organs.nutrients are ingested at the mouth.nutrients enter the capillaries of the circulatory system. sequence

How can scientists test their ideas about the origin of the universe if they can't physically interact with or study?

Ascientific idea becomes valid when it is what?